In a note to parents, Superintendent of Schools in Seaford, Adele Pecora, revealed an employee in the district tested positive for COVID-19.
School officials say the person had been in Seaford High School and Seaford Middle School last week.
The school says they are proceeding with the guidance provided by the New York State Department of Health and requiring schools to close for 24 hours while the local health department investigates.
District employees will not be permitted at the buildings while they are professionally cleaned and disinfected.
The Nassau County Department of Health has advised the district to contact persons who may potentially have been exposed.
Due to privacy laws, the districts says it is not able to share the identity of the individual or details about the case.
PHOTOS: The impact of coronavirus around the world
undefined